little help would be sweet

[inkslingrrr]

Finally getting at my own build(71 chev c10 custom) and after removing the gas tank from behind the seat I noticed the PO had done a little repair(if you can call it that).
The inner cab corner/ rear cab floor whatever it be called has been replace with a metal I can bend with my fingers...
So my question is:
-do I/should need to remove inner rocker as well as outer rocker or can I do this all from the cab corner? Now the outer and inner have been replaced new before this was noticed on the drivers side, but passenger side is un-touched atm.

so any help and pics cuz im a visual guy would so be greatly appreciated!!!!
and I will continue to flip through the builds as well.

thanks from the great white north!!